細胞膜和細胞表面ppt課件-展示頁
2025-05-13 12:01本頁面
【正文】 y are mixed with phospholipids. 膜的側(cè)面流動性和脂肪酸鏈長度，飽和或不飽和脂肪酸，及溫度有關(guān)。細胞膜與細胞表面 plasma membrane and cell surface 膜脂 Lipid Composition and Structural Organization ? 生物膜的結(jié)構(gòu)基礎，脂質(zhì)雙分子層 ? Biomembranes: Lipid Composition and Structural Organization 膜脂 ——生物膜的基本組成成分 Three Classes of Lipids Are Found in Biomembranes ? 膜脂可分為三大類，磷脂（磷脂甘油），鞘脂和膽固醇 ? A typical biomembrane is assembled from phosphoglycerides,sphingolipids, and steroids. All three classes of lipids are amphipathic molecules having a polar (hydrophilic) head group and hydrophobic tail. 磷脂甘油 3磷酸甘油的衍生物 the most abundant class of lipids in most membranes, are derivatives of glycerol 3phosphate . 磷脂具有 2個脂?；鶚?gòu)成的疏水性尾部和與磷酸相連的親水性頭部 A typical phosphoglyceride molecule consists of a hydrophobic tail posed of two fatty acyl chains esterified to the two hydroxyl groups in glycerol phosphate and a polar head group attached to the phosphate group. Phosphatidylethanolamine 磷脂酰乙醇胺 Phosphatidylcholine 磷脂酰膽堿 Phosphatidylserine 磷脂酰絲氨酸 Phosphatidylinositol 磷脂酰肌醇 紅色部分為鞘氨醇，具有一個長的 碳氫鏈 ，一個 氨基 與脂肪酸鏈相連，一個 羥基 和磷酸相連 All of these pounds are derived from sphingosine, an amino alcohol with a long hydrocarbon chain, and contain a longchain fatty acid attached to the sphingosine amino group. sphingomyelins 鞘磷脂 Glucosylcerebroside，葡萄糖神經(jīng)酰胺，是一種糖脂，糖脂在神經(jīng)組織最多 Glycolipids constitute 2–10 percent of the total lipid in plasma membranes。 they are most abundant in nervous tissue. ? 膽固醇，有 4個環(huán)，一個羥基（親水） ? 前面兩種膜脂可以單獨或混合形成脂雙層，膽固醇則不能形成脂雙層。 膜脂的流動性限制了膜蛋白的流動性 ? The ability of lipids to diffuse laterally in a bilayer indicates that it can act as a fluid. The degree of bilayer fluidity depends on the lipid position ? Long, saturated fatty acyl chains have the greatest tendency to aggregate, packing tightly together into a gellike state. 膜蛋白熒光標記脫色恢復實驗 膜脂的運動方式 ? 沿膜平面?zhèn)认蜻\動 ? 圍繞軸心的自旋 ? 分子尾部的擺動 ? 雙層分子間的翻轉(zhuǎn) ? 依賴于翻轉(zhuǎn)酶 flipase 脂筏 Lipid raft ? 鞘脂和膽固醇形成，厚度和構(gòu)成均和周圍不同，脂筏可以集中某些蛋白。 脂質(zhì)體的類型和應用 (a)水溶液中的磷脂分子團； (b)球形脂質(zhì)體； (c)平面脂質(zhì)體膜； (d）用于疾病治療的脂質(zhì)體的示意圖 脂質(zhì)體的應用 研究膜脂與膜蛋白及其生物學性質(zhì)； 脂質(zhì)體中裹入 DNA可用于基因轉(zhuǎn)移； 在臨床治療中 ,脂質(zhì)體作為藥物或酶等載體 膜蛋白 Biomembranes: Protein Components and Basic Functions ? 膜蛋白分內(nèi)在蛋白，錨定蛋白，外周蛋白 ? Proteins Interact with Membranes in Three Different Ways ? Integral membrane proteins, ? Lipidanchored membrane proteins ? Peripheral membrane proteins 蛋白穿膜
教學課件相關(guān)推薦
鄂ICP備17016276號-1